Windswept_ The Story of Wind and Weather - Marq de Villiers [103]
The most ardent disagreements among scientists, though, are still about what concentrations of CO represent a real danger to life.
One of the main areas of debate is the role of the oceans. Oceanic CO is rising as quickly as atmospheric CO. An NOAA study estimated that the oceans have absorbed 120 billion tons of carbon in the last century, most of it generated by the burning of coal, oil, and gas. The current rate of absorption is 20 to 25 million tons of CO a day—a rate not seen on this planet for twenty million years. The accumulation is one hundred times faster than between the last two ice ages.20 The oceans, then, are acting as carbon sinks—each year humanity pours somewhere around 8 billion tons of CO into the atmosphere, but less than half of it stays there. The rest goes into the oceans.
One of the many things complicating the inquiry is the relationship between carbon dioxide, the principal greenhouse gas, and sulfur dioxide, a common pollutant. If—a very big if—we act to reduce CO2, this will in theory slow the global warming trend. But because we are concurrently reducing SO?, which will itself have a slight warming effect, the results could be masked. "There are so many similarly fuzzy factors—ranging from aerosol particles to clouds of cosmic radiation—that many parts of the world could endure unfamiliar weather patterns and maybe even freakish storms for years without knowing how it is happening or what to do about it," says Vijay Vaitheeswaran.21
Some of the CO in the air and the sea is absorbed naturally Mollusks, for example, take it from the oceans to make their shells, so farming mussels must be a good thing. On land, forests take CO from the air to make wood; measurements taken in the air over large forests show that the CO2 concentrations are ten parts per million lower than elsewhere. However, the optimistic theory that increased carbon levels will make forests grow faster seems to be wrong, because trees more quickly run out of other essential nutrients. Ironically, cutting down old-growth forests, a major concern of the Green movement, might actually help—young growing trees need more carbon than older ones.22
In February 2005 a study found that humans are indeed warming the oceans, down to thousands of meters, almost certainly due to increased carbon dioxide caused by the burning of fossil fuels and the consequent greenhouse effect. The study's lead author was Tim Barnett of Scripps Institution of Oceanography in La Jolla, California. "This should wipe out most of the uncertainty about the reality of global warming," he asserted.23
All this connects, of course, directly to winds and to weather, albeit in ways difficult to untangle. If global warming does indeed cause the ocean temperatures to rise, and hurricanes need warm water . . . does it follow that there will be more, and more severe, hurricanes? It would seem so if you believe the news. In fact, if you follow the news even cursorily, you'll see that it's been a given for some years that global warming will produce more severe weather more often. It's an assumption that seems to have been generally accepted, even by many experts. It may even be true. But it isn't necessarily true.
The IPCC's 2001 report stated that there was no evidence tropical cyclones had increased in intensity or number, although there was evidence